the organism and with the temperature. Increased sweating, for example, 

 removes water continuously. And unless this is made up by taking in more 

 water, the urine will be more concentrated. On the other hand, any excess 

 of water taken in is quickly removed by the kidneys, so that the urine be- 

 comes diluted. 



During strenuous exercise albumin may be temporarily present in the 



Ward's Natural Science Establishment, Inc. 



URINE-COLLECTING TUBES IN A KIDNEY 



If the urine tubes of a sheep's kidney are filled with latex and all the tissues are 

 then corroded away chemically, there remains a "latex cast" of the tube system. 

 This shows how the urine discharged from the thousands of uriniferous tubules in 

 the cortex of the kidney is collected in the pelvis 



220 



